Impact of vegetation geometry and distribution on bedload transport

沿海沼泽可以减弱风暴潮和海浪，保护生命和财产。这种绿色基础设施还改善了水质，并为具有重要经济价值的渔业提供了栖息地。同样，洪泛区的植被减少了洪峰，增强了堤岸的稳定性，并减少了向河道输送的营养物质。由于这些好处，资源管理者提倡对沿河走廊和沿海地区的植被景观进行补种和生态管理。美国每年花费数十亿美元来恢复这些景观。恢复工作，包括重建植被和将泥沙引向受侵蚀地区，需要对这一项目将有助于提供的植被地区的泥沙迁移和保留有基本的了解。除了这项研究可能产生的这些预期的社会效益外，该项目还将培训一名博士生，每年夏天支持一名本科生，并包括在波士顿地区的初中和高中推广。该研究项目将开发泥沙运移作为水流和植被特征函数的物理预测。新的模型将通过使用日益复杂的模型植被的一系列实验室实验来开发，这些模型将建立对河道内植被几何形状和分布如何影响流速、湍流和泥沙输送的理解。实验将记录速度和渠道尺度的沉积物通量，并将使用激光扫描来跟踪水深测量的演变。通过与美国填海局的合作，将促进新模型在全面修复项目中的实际应用。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Coastal marshes attenuate storm surge and waves, protecting life and property. This green infrastructure also improves water quality and provides habitat for economically important fisheries. Similarly, floodplain vegetation reduces flood peaks, enhances bank stability, and reduces nutrient loading to river channels. Because of these benefits, resource managers advocate the replanting and ecological management of vegetated landscapes along river corridors and in coastal zones. The US spends billions of dollars each year to restore these landscapes. The restoration efforts, which include the re-establishment of vegetation and the diversion of sediment into eroded areas, require a fundamental understanding of sediment transport and retention in vegetated regions that this project will help provide. In addition to these desired societal benefits that could stem from this research, the project will also train one doctoral student, support one undergraduate student each summer, and include outreach in Boston-area middle and high schools.This research project will develop physical predictions of sediment transport as a function of flow and vegetation characteristics. The new models will be developed through a series of laboratory experiments using model vegetation of increasing complexity that will build an understanding of how vegetation geometry and distribution within a channel impact velocity, turbulence, and sediment transport. Experiments will record velocity and channel-scale sediment flux, and will use laser-scans to track bathymetric evolution. The transfer of new models to practical application in the full-scale restoration projects will be facilitated through collaboration with the US Bureau of Reclamation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.